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This research paper focuses on the use of solid biomass waste, specifically a combination of Polyalthia longifolia seed (PLSF) and graphite (GH) powder, as reinforcements in vinyl ester (VE) composites. The composites were produced via the hand layup method, with the filler concentration varying from 0 to 15 wt% of PLSF and 0–9 wt% of graphite. The objective was to examine the influence of the hybrid filler on the mechanical characteristics of the composites. The mechanical properties of composites prepared from P. longifolia seeds and graphite powder were experimentally characterized. These properties included tensile strength, flexural strength, impact resistance, and hardness. The hybrid composite had a maximum tensile strength of 48.4 MPa, and its tensile modulus was 1.66 GPa. The hybrid filler at 15% wt% of PLSF and 6% of graphite has the highest flexural strength, which is around 148 MPa. The ultimate impact strength and hardness were measured to be 41.3 kJ/m2 and 44.5, respectively, after the addition of 15 and 6 wt% of hybrid filler. In comparison to neat vinyl ester resin, the PLSF/GH‐VE composites exhibited an increase in tensile, flexural, impact, and hardness of 2.69, 1.82, 3.03, and 1.59 times, respectively. Hybrid composite surfaces were analyzed using scanning electron microscopes to determine surface characteristics and fractured surfaces. In addition, the PLSF/GH‐VE composites have been utilized in the production of components for four‐wheelers. Highlights: Investigated the impact of hybrid filler‐reinforced vinyl ester composites.Mechanical and thermal properties were experimentally characterized.Surface characteristics and fractured surfaces were examined.PLSF/GH‐VE composites are used in producing components for four‐wheelers. [ABSTRACT FROM AUTHOR]

3D printing has witnessed a remarkable surge in popularity due to its flexibility in design and adaptability as a manufacturing technique to nearly each industrial area. This study focuses on harnessing the technological versatility of 3D printing by utilizing both standard poly lactic acid (PLA) and copper powder‐doped PLA to fabricate intricate structures through a layer‐by‐layer additive manufacturing process. The other innovation introduced here lies in the postprocessing step, which involves salt remelting. The mechanical properties of 3D‐printed standard test specimens undergo comprehensive assessment, encompassing bending and tensile evaluations, hardness measurements, density assessments, dimensional stability analyses, and wear resistance examinations. Utilizing copper powder‐doped PLA for the initial and final layers in XYZ‐oriented prints enables multimaterial printing, resulting in an ≈14% increase in tensile strength. Subsequently, subjecting this multimaterial composite to salt remelting elevates the strength enhancement to ≈16%, accompanied by a significant boost in rigidity by reducing voids in cross‐sectional area. In addition, scanning electron microscope images are captured, allowing for a detailed morphological analysis, which is then correlated with the findings of the various tests performed. This research unveils the potential of 3D printing technology in crafting materials with tailored mechanical properties, advancing its applicability in numerous industrial sectors. [ABSTRACT FROM AUTHOR]

Using Camellia oleifera shell as raw materials to preparative SiC ceramics by warm‐press forming and sintering is proposed in this paper. Warm‐press forming before preparing for the C. oleifera shell‐based SiC ceramics is beneficial to obtain the internal uniform and suitable pore structure of the cylindrical sample. Thermogravimetric analysis with differential scanning calorimetry was applied to analyze the pyrolysis behavior of C. oleiefra shell and phenolic resin. The scanning electron microscope and X‐ray diffraction were used to investigate the properties of C. oleifera shell‐based SiC ceramics. Then, the response surface method was applied to establish a multivariate prediction model based on the process parameters of warm‐press forming. And the regression equations of porosity and bending strength of COS‐SiC are obtained. The result demonstrated that the predicted and experimental values can be in good agreement for the model. By comparing the F‐value, it is found that the forming temperature and pressure during the process of warm‐press forming have a more significant influence on the porosity and bending strength of SiC ceramics. The optimization process parameters were obtained as follows: forming temperature 153°C, pressure 35 MPa, and holding time 30 min. [ABSTRACT FROM AUTHOR]

In this article, the effect of Ce element on the microstructure and mechanical properties was studied by Ce addition to the hot‐formed steel. Scanning electron microscope and energy dispersive spectrometer (SEM‐EDS) was used to analyze the improvement effect of Ce on inclusions and the effect of inclusions on fracture behavior; Electron back scattering diffractometer (EBSD) was used to analyze the refinement and strengthening effect of Ce on martensitic grains; transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) was used to analyze the microstructure strengthening effect and microalloying effect of solid solution Ce in hot‐formed steel. Through a systematic analysis of mechanical properties and microstructure, the mechanism of Ce enhances the strength and elongation of hot‐formed steel was clarified. Besides, this work provides a research basis for further improving the safety and machinability of hot‐formed steel. [ABSTRACT FROM AUTHOR]

The tensile behavior of a flexible epoxy resin reinforced with knitted reinforcements from various fiber materials was comprehensively studied in the wale and course direction. By measuring dry yarns, temperature‐treated yarns, dry knitted fabrics and flexible composites, the effect of the fiber material and the knitted fabric on the tensile properties was analyzed. The interlock knit structure strongly affected the deformation behavior of the flexible composites which differed significantly from the dry knitted fabrics. The deformation behavior of the flexible composites was monitored using digital image correlation which revealed the formation of cracks and high local strain differences in the course direction for all fiber materials. This was linked to fiber‐matrix debonding by scanning electron microscope observations. In the wale direction, the deformation of the knitted structure under tensile load led to plastic deformation of the matrix material. Overall, with yarns from recycled thermoplastic fibers, a higher maximum stress and strain at break was achieved compared to bio‐based fibers. However, irreversible damage occurred for all fiber materials at similar strain values. Highlights: Tensile tests on yarns, knitted fabrics and flexible composites.Investigation of the effect of fiber material on mechanical properties.High local strain differences in composites due to knitted structure.Fiber‐matrix debonding in course direction.Plastic deformation of the matrix material in the wale direction. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of stir‐casting process parameters, including stirring speed, stirring time, and weight % of the ceramic microsphere, on the fabrication of an aluminium 6061‐ceramic microsphere composite. Experiments are conducted using a full‐factorial design approach to determine the effect of variables on mechanical properties. A field effect scanning electron microscope is used to analyze the fracture surfaces of the test specimen. Further, the results are subjected to the Anderson‐darling normality test to validate the accuracy of the model, and finally, an analysis of variance is performed to identify the most significant parameters that affect the mechanical properties. The results confirm the validity of the designed experimental model for enhancing the mechanical properties of the aluminium 6061‐ceramic microsphere composite. The optimum mechanical properties are attained for a stirring speed of 600 min−1, stirring time of 15 min, and 5 weight % of reinforcement. Furthermore, the weight percentage of the ceramic microsphere increase, the ductility of the composite decreases while its strength and hardness increase. Finally, the analysis of variance shows that all parameters significantly impact the mechanical properties of the designed composite. [ABSTRACT FROM AUTHOR]

This research aims to study the effect of injection parameters on the mechanical properties of the developed green composites. Natural flax fibre and biodegradable polymer, polylactic acid was chosen to develop the green composites. The flax fibre was chemically treated using sodium hydroxide to fabricate the green composite by injection moulding. The injection parameters namely (i) injection pressure (bar), (ii) injection speed (mm/s), and (iii) injection temperature (°C) was considered to investigate their effect on the mechanical properties of developed polylactic acid/flax green composites. The mechanical properties, such as (a) tensile strength (TS), (b) tensile modulus (TM), (c) percentage elongation under tensile loading (PET), (d) flexural strength (FS), (e) flexural modulus (FM), (f) percentage elongation under flexural loading (PEF), (g) compressive strength (CS), and (h) shear strength (SS) was evaluated under different injection conditions. Furthermore, the morphology of the mechanically tested specimens was investigated using a scanning electron microscope. Grey relational analysis was performed to find the optimal injection condition. The optimum injection condition depicting superior mechanical properties was found at injection parameters combination of 90 bar (injection pressure), 60 mm/s (injection speed), and 165 °C (injection temperature). [ABSTRACT FROM AUTHOR]

The microstructure and properties of an AlSi10Mg alloy produced by selective laser melting were examined using optical microscopes, scanning electron microscopes, electron backscattered diffraction, and x‐ray diffraction. The results show that the mechanical characteristics of selective laser melting formed AlSi10Mg alloy is superior to those of traditional sand cast AlSi10Mg alloy due to fine grain strengthening and solid solution strengthening. AlSi10Mg alloy formed by selective laser melting is mainly composed of α‐aluminum solid solution, eutectic silicon with network structure and a small amount of Magnesium silicon precipitated phase, and different cross‐sections have unique microstructures and properties. The XOY plane is composed primarily of equiaxed grains with an average grain size of 7.34 μm and a {001} <100> cubic texture, and it has a hardness value of 130.7 HV 0.2. The majority of the YOZ plane, which has a {111}<110> brass R texture and a hardness value of 108.9 HV 0.2, comprises columnar crystals with an average grain size of 8.42 μm. [ABSTRACT FROM AUTHOR]

In this study, we investigated how the chemical structural properties, mechanical properties, and morphology of large‐size graphene platelets (LGPs) doped glass fabric (GF)/epoxy composites are affected by varying loading amounts of LGPs. Scanning electron microscope results revealed that the dispersion and filling effect of LGPs can improve the flowability of the resin, reducing the aggregation and shrinkage of the resin on the glass fabric surface, thereby facilitating better resin infiltration and coverage of the glass fabric surface. From the spectrum analysis, the binding of LGPs with epoxy resin was the physical combination, without new chemical groups generated during the curing process. The addition of LGPs improved the ratio of the crystalline phases in the composites, from 30.00% of the GF/epoxy to 57.50% of the GF/epoxy@2.2LGPs. Mechanical properties indicated that the composites exhibited greater tensile strength than pure GF, which progressively increased with increasing LGPs content until it reached 1.5 wt%, then the tensile strength starts to decrease. And the GF/epoxy@1.5 LGPs exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites, which achieved a satisfactory enhancement under relatively low loading content. Highlights: The effect of the large‐size graphene platelets (LGPs) on the properties of glass fabric (GF)/epoxy composites.Compared to the glass fabric/epoxy composite, the LGPs doped composite possessed a much higher storage modulus (E′).The LGPs doped composite exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites.The addition of LGPs improved the ratio of the crystalline phases in the composites. [ABSTRACT FROM AUTHOR]

In recent decades, considering environmental issues, partial replacement of Portland cement with supplementary cementitious material (SCM), namely ground granulated blast furnace slag (GGBS), has been in the spotlight of research. On the other hand, carbon‐based nanomaterials, especially graphene oxide (GO), are recognized as an extraordinary additive with special characteristics that can be included in cementitious materials. In this research, the impact of GGBS on the mechanical properties and durability of GO‐modified mortars was investigated at 28 and 90 days. The results demonstrate that by increasing the content of GGBS, a decrease in the flexural and compressive strength compared to plain cement sample was seen. On the other hand, incorporation of GGBS and GO led to higher strength compared to GO‐cement mortar. Also, the compressive strength of the sample containing 20% GGBS and 0.03% GO was 38.7% higher than the plain cement sample at 90 days. On the other hand, adding GGBS to a GO‐reinforced sample resulted in a more durable specimen against chloride and acid environments. The sample made of 40% GGBS in GO‐modified mortar not only has the best efficiency in harsh environments but also has the lowest water absorption. This mortar improved the migration coefficient, mass loss in HCl solution, and initial sorptivity by 20.1%, 57.7%, and 37.1%, respectively. Moreover, the mentioned sample had a denser microstructure with smaller cracks compared to other samples, based on scanning electron microscope (SEM) images. [ABSTRACT FROM AUTHOR]

Due to the depletion of petro‐based sources and environmental consciousness, researchers are striving to replace synthetic fibers and resins in composites with bio‐sourced ones without compromising their properties. In this regard, the present study investigates the effect of partially replacing epoxy moieties with castor oil based bio‐resins on various properties of epoxy resin and its flax fiber reinforced composite system to achieve sustainable materials, thereby encouraging the bio‐based theme. Base‐catalyzed transesterification was used to synthesize epoxy methyl ricinoleate (EMR) as a low viscous reactive green monomer derived from epoxidized castor oil (ECO). The influence of both ECO and EMR bio‐resin on various mechanical, thermo‐mechanical properties, free mode vibration, and water absorption of epoxy and its composites were studied. The composition with 20% of ECO and EMR was optimized based on stiffness‐toughness balance. The inclusion of 20% EMR significantly escalated the tensile, impact, and fracture toughness properties of epoxy composites by 6.45%, 12.8%, and 14.2%, respectively. The strong fiber‐matrix interface was confirmed by increased pullout adhesion by 21% and 35.1% due to the addition of ECO and EMR, respectively. Dynamic mechanical analyzer revealed a 12% higher storage modulus for EMR modified composites than ECO counterparts. Scanning electron microscope morphology revealed superior interfacial adhesion between fiber and matrix in case of EMR modified bio‐composite, which resulted in a lower water diffusion coefficient than ECO modified bio‐composite. These results showed that the 20% EMR customized epoxy composite is dimensionally stable with improved mechanical properties and may act as a green alternative to petro‐sourced epoxy composites in automotive and semistructural applications. Highlights: Effects of castor oil based bio‐resins on epoxy composites are studied.Composites with significant bio‐content (~50 wt%) are developed.EMR modified epoxy composites exhibited improved mechanical properties.A strong fiber‐matrix interface was confirmed by increased pullout adhesion.Reduction in pot life of epoxy was observed on adding ECO and EMR. [ABSTRACT FROM AUTHOR]

In a nitrogen atmosphere, a novel composite, Poly(Acrylonitrile‐co‐Acrylamide)/crab shell powder, was synthesized by combining two monomers, acrylonitrile (AN) and acrylamide (Aam), with varying weight percentages of crab shell powder (CSP) as bio‐filler. The synthesized composite Poly (AN‐co‐Aam)/CSP, copolymer Poly (AN‐co‐Aam), and CSP were characterized using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric (TGA) analysis, derivative thermogravimetric (DTG) analysis, and a scanning electron microscope (SEM). The mechanical properties, like tensile, flexural, and impact strengths, were studied. The hardness, biodegradability, and water absorbency properties have been studied using appropriate methodologies. The SEM images and FTIR data confirm the appropriate synthesis of the composite material and the uniform distribution of CSP. The mechanical strength increases with the rise in concentration of CSP up to 20 wt. % and then gradually decreases. The thermal analysis reveals that the composite exhibits adequate thermal stability. The artificial neural network (ANN) model is used for the prediction of mechanical properties, which shows adequate results with the experimental results. The training and test datasets use a correlation factor associated with this analysis that is higher than 0.9, which confirms that the expected values of the mechanical performance are an excellent comparison to the experimental value. [ABSTRACT FROM AUTHOR]

In the present investigation, moringa oleifera and bamboo fibers extracted from Ethiopia are studied to understand their mechanical properties. Three types of woven composites namely moringa/epoxy, bamboo/epoxy and moringa/bamboo/epoxy (hybrid) are fabricated by maintaining 60 vol% fiber content. Additionally, neat epoxy samples are prepared for comparison. Tensile and flexural properties are investigated in terms of strength and modulus. Tensile test results depict brittle failure for all composites and infer increase in fracture strain of woven composites as compared with neat epoxy. Tensile modulus and strength of woven composites increase in the range of 19%–39% and 18%–281%, respectively as compared with neat ones. Flexural stress–strain profiles of neat epoxy, moringa/epoxy and moringa/bamboo/epoxy composites linear curves until failure indicating brittle mode while bamboo/epoxy composites shows non‐linear stress–strain profiles revealing non‐brittle mode of failure. Flexural properties exhibited by bamboo/epoxy and moringa/bamboo/epoxy reveal comparable properties to each other yet superior than moringa/epoxy and neat epoxy composites mainly attributed to the good bonding of constituents and compatibility. All the woven composites reveal an increase in flexural modulus and strength and are in the range of 31%–96% and 5.79%–51.12%, higher than the neat epoxy. Finally, fractured surfaces of specimens are analyzed using scanning electron microscope to understand the structure property correlations. [ABSTRACT FROM AUTHOR]

Spark plasma sintering (SPS) is a new sintering method having shorter sintering time and higher densification speed than the traditional sintering methods. In this paper, the Si3N4/TiC ceramic tool material is sintered by SPS. The microstructure and mechanical properties of the material under different sintering parameters are compared. The sintering process of the material is then analyzed, and the best sintering parameters are obtained. Heat the material to 1600°C and keep the temperature for 15 min, then continue to heat to 1700°C and keep the temperature for 10 min, Si3N4/TiC ceramic tool material has high mechanical properties, its bending strength, fracture toughness, and Vickers hardness are 959 MPa, 8.61 MPa·m1/2, and 15.21 GPa, respectively. The scanning electron microscope (SEM) analysis shows that under this condition, the sintering additives and Si3N4/TiC material form the liquid phase, which makes the Si3N4 particles rearrange, dissolve, precipitate, and transform into rod shape β‐Si3N4. In addition, under the action of pulse current and external pressure, electric sparks are generated between TiC particles, which allows the material transfer and particle refinement. Therefore, the β‐Si3N4 has uniform grain size, and it is vertically and horizontally arranged in the structure, which makes the material have excellent mechanical properties. [ABSTRACT FROM AUTHOR]

This study investigated the feasibility of using two types of waste glass sand as fine aggregate replacement in ambient cured alkali‐activated mortars (AAMs). Fly ash (FA) and ground granulated blast furnace slag were used as aluminosilicate source materials to produce the AAMs. The waste glass sand was used to replace 0%, 25%, 50%, 75%, and 100% fine aggregate (by mass) in AAMs. The influences of the use of waste glass sand, for the replacement of fine aggregate, on slump flow, setting time, compressive strength, and flexural strength of ambient cured AAMs were evaluated. It was found that the slump flow and setting time of ambient cured AAMs significantly increased as the percentage of replacement of fine aggregate by waste glass sand increased. However, the compressive and flexural strengths of ambient cured AAMs decreased when 50% and over fine aggregate were replaced by waste glass sand. The ambient cured AAMs with 25% replacement of fine aggregate with waste glass sand achieved the highest compressive and flexural strengths. Scanning electron microscope analysis indicated that the increase in the compressive strength and flexural strength of AAMs was due to the bridging‐like effect and filling effect provided by the waste glass sand. The use of waste glass sand as a partial replacement of fine aggregate in ambient cured AAMs was found to be feasible. In addition, 25% of the fine aggregate replaced by waste glass sand resulted in the best mechanical properties for ambient cured AAMs. [ABSTRACT FROM AUTHOR]

For commercial civil applications of laminated composite material, characterizations to forecast the interlaminar shear behavior and viscoelastic response across a wide temperature range are essential. In this study, the interlaminar shear strength (ILSS) of glass/epoxy (GE) composites dispersed with binary nanofillers nanosilica‐multilayer graphene (NS‐MLG) and nanosilica‐nanoclay (NS‐NC) was analyzed at an in‐situ testing temperature of 20, 70, and 110°C. Further, the viscoelastic property of the composites was studied using a dynamic mechanical thermal analyzer (DMTA) in the temperature range of 35–165°C. An increase in the ILSS value of around 9% and 10% was observed at room temperature for GE/MLG‐NS and GE/NC‐NS, respectively, compared to control GE composites. In contrast, the trend was seen to change at higher temperatures. There was a slight decrement in the storage modulus (E′) of GE/MLG‐NS and GE/NC‐NS composites in the glassy region compared to control GE composites. The mean Tg of the GE composite (control) was nearly 107.3°C when the E′ decline onset temperature was taken into account, but after the addition of MLG‐NS, it was 10.1°C below. The mean Tg of GE/NC‐NS was determined to be 106.3°C, and in the glass transition as well as rubbery regions, it was observed to compete with the E′ value of the control GE composites. Fractography was done using micrographs obtained from environmental scanning electron microscope (ESEM). Traces of polymeric material found at the fiber surface certified the improved interfacial adhesion between glass fiber and polymer in the matrix‐modified composite samples. [ABSTRACT FROM AUTHOR]

The potential advantage of plasma treated polyethylene (PEP) in mechanical properties was studied in this research. Recycled carbon fiber (CF) was the filler used for this hand layup technique. During fabrication, 4–14 wt% CF was incorporated into PEP and the results showed the impact of both filler and plasma treatment in enhancing the mechanical strength of polymer composites. Tensile results improved from 17.51 to 22.51 MPa in the polyethylene (PE) matrix. Scanning electron microscope (SEM) results showed untreated PE composites with fiber and matrix breakages as also voids reducing the compatibility of the PE/CF phases. The maximum flexural property of 25.5 MPa was observed in 10 wt% CF/PE treated with plasma. This combination was tried with different fabrication conditions in a temperature range of 180–220°C and time duration of 20–30 min. It was clearly seen that CF/PE combinations at a temperature of 180°C and time duration of 20 min had maximum tensile and flexural strength. The optimization using Taguchi method proved the significance of CF content in enhancing the mechanical properties. It also observed better tensile strength, flexural strength properties with 10 wt% CF, 180°C temperature, 20 min time from the results. Surface images of this condition showed more dispersed CF in the PE than other combinations due to optimum temperature and time duration during fabrication. [ABSTRACT FROM AUTHOR]

3D printing of continuous fiber reinforce plastics (CCFRP) with fused deposition modeling is a burgeoning manufacturing method because of its exceptional mechanical properties. Nevertheless, it cannot manufacture parts at high speeds. Using laser heating instead of the traditional resistive heating in 3D printing of CCFRP has the potential to improve printing speed owing to its high heating efficiency. In this article, a process of laser‐assisted rapid 3D printing of CCFRP is proposed. The heating process of CCFRP by laser is analyzed and verified. The linear relation between printing speed and laser power is established. The experiments demonstrate that the printing speed is increased to 30 mm/s with the laser. The mechanical properties of printed parts, though enhanced as the printing speed and laser power increase, are better than those obtained by traditional methods. Scanning electron microscope images and experiments reveal that proper laser power is conducive to the melting of plastics, strengthening interlayer bonding, and reducing voids under roller pressure. Nonetheless, excessive laser power ablates the plastic, resulting in increased voids. [ABSTRACT FROM AUTHOR]

By using SU‐8010 thermal field scanning electron microscope, JEM‐2100 transmission electron microscope, MHRS‐150 Rockwell hardness tester and X‐ray diffractometer to observe the microstructure and detect residual stress, and the measurement of the hardness and the tensile properties, the effect of stabilization treatment on the microstructure, size change, and mechanical properties of the austempered M50 steel is studied. Results show that the residue of austenite and the carbides precipitated during the bainite transformation after austempering lead to lattice shrinkage, which reduces the size of the bearing ring. The release of quenching stress after tempering increases the size. During austempering and tempering, the size fluctuates between −0.29 and 0.23 mm. After the bearing ring is stabilized for 3 times, the precipitation of filamentous carbides reaches the maximum, and the number of carbides does not increase obviously after 5 times of stabilization. The size fluctuation range is −0.9 to 0.7 μm. After M50 steel is stabilized, the transformation of residual austenite to martensite and the precipitation of carbides increase the hardness, and the coarsening of carbides reduces the ductility. The tensile strength increases from 2550 to 2650 MPa, which is related to the dispersion strengthening of carbides and their pinning effect on dislocations. [ABSTRACT FROM AUTHOR]

In this research, rotomoulded samples of polyethylene (PE) were mechanically tested to find better applications. The mold was kept in an oven at 260°C with forced convection. Total fabrication time depended on peak internal air temperature (PIAT) used with 200, 220 and 240°C to confirm the fabrication conditions. The plasma treatment of PE and recycled carbon fiber (CF) was used for the improvement of properties. Maximum tensile strength (TS) of 23.1 MPa was observed in 10 wt% CF/PE composites. Scanning electron microscope (SEM) results revealed good mechanical interlocking with higher chemical interaction of carbon fiber of up to 10 wt% with plasma polyethylene leading to good mechanical properties in the composites. Flexural strength (FS) of 19.98–26.02 MPa in the properties was observed plasma treated in the PE with CF (3–10 wt%) combination. Agglomeration in the carbon fiber lowered flexural properties of 13, 15 wt% filler with both plasma and non‐plasma PE. The CF (3–10 wt%) with plasma PE showed enhanced impact strength (IS) from 6.84 to 8.64 KJ/m2. Maximum TS, FS and IS were observed with peak internal air temperature (PIAT) of 200°C. Surface images showed even distribution of fiber and resin in the plasma treated matrix in 5 wt% CF combinations. The differential scanning calorimetry (DSC) results do not show fluctuations in the melting and crystallization temperatures of the samples after plasma treatment. [ABSTRACT FROM AUTHOR]

The degree of the imidization reaction determines the properties of polyimide (PI) obtained by the thermal curing process. In this paper, amine‐modified graphene (N‐GO) was designed by integrating pyridine structure with graphene and acting as a catalyst to promote the imidization reaction of PI. Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) were then used to confirm the morphology and structure of N‐GO. The catalytic effect of N‐GO in imidization reaction was obtained by FTIR and subsequently characterized by differential scanning calorimetry (DSC) and water contact angle (WCA). Surprising results suggest that the agglomeration of N‐GO can also contribute to solid‐phase reactions in imidization reactions. Lastly, the results of mechanical property tests, thermogravimetric analysis (TGA), and FTIR demonstrated that the composite films showed excellent tensile strength (176.2 MPa) and thermal stability (513.0 °C); at the same content, only 0.5% of N‐GO addition reduced the imidization temperature by 20°C, exhibiting remarkable enhancement effects. This research is a valuable solution to the problem in performance caused by low‐temperature curing agent residues in films, and it is expected to be used in the microelectronics field. [ABSTRACT FROM AUTHOR]

It is aimed to explain different tensile elongations in 18Cr–8Ni austenitic stainless steel (ASS) with various microstructures having the same yield strength by comparing the deformation mechanisms. The as‐received ASS is cold‐rolled (CR) at room temperature with thickness reductions of 10% and 90% (achieved following 14 passes). The ultra‐fine grain/fine grain (UFG/FG, average grain size (diameter): 0.5–2 μm) structure is developed by annealing the 90% CR structure at 850 °C over 300 s. The optical, scanning and transmission electron microscope, electron backscatter diffraction, and X‐ray diffraction techniques are applied to the microstructural features. The as‐received specimen contained equiaxed austenite and equiaxed dislocation cells, stacking faults, deformation twins (DTs), and strain‐induced martensite (SIM) coexist in the 10% CR and UFG/FG samples. Tensile tests are conducted, and the results reveal that 10% CR and UFG/FG structures exhibited similar yield strengths (550 MPa) under conditions of varying elongation properties, which is attributed to differences in the microstructure‐dependent deformation mechanisms. Dislocation slip (≈10 area%; newly formed), DTs, and SIM (≈44 vol%; newly formed) are observed in the 10% CR structure. The presence of numerous dislocation slips (≈50 area%; newly formed) and a small amount of DTs and SIMs are observed in UFG/FG structure. [ABSTRACT FROM AUTHOR]

In this study, the effect of sonication time on the mechanical properties of graphene nanoplatelets (GnPs) glass fiber composites were discussed. The Sonication process is one of the best techniques to ensure uniform dispersion of nanofillers into the polymer matrix; otherwise, they form agglomerates of multilayers. To fulfill the massive demand for mass production, ultrasonic bath‐type sonication were deployed. In this study, 0, 1, 2, 3, 4, and 5 wt% of GnPs were added with epoxy at different sonication durations, precisely 0, 20, 40, and 60 min. Other sonication process parameters were kept constant with a sonication frequency of 28 KHz. Bidirectional glass fabric materials was used as reinforcement material in the fabrication of the laminates. In total, 21 laminates were fabricated using the hand lay‐up technique in various amalgamations. The tensile and flexural specimens were cut from the laminates as per the standards to determine their mechanical properties. The scanning electron microscope (SEM) images were used for the structural analysis of the glass fiber reinforced GnPs/epoxy composite. Surface morphology of GnPs becomes more wrinkled, resulting in a stronger graphene/epoxy matrix interface, enhancing the tensile strength and tensile modulus performance of the nano‐composites increases up to 37.12% and 66.30%, the flexural strength and flexural modulus performance of the nano‐composites increases up to 55.74% and 91.23% respectively. Based on the investigations, the influence of the GnPs percentage and the sonication duration for the preparation of the nano‐composites with the help of technique for order of preference by similarity to ideal solution (TOPSIS) optimization technique. [ABSTRACT FROM AUTHOR]

The need for eco‐friendly materials has been attracted due to renewability, abundance availability, low cost, and so on. Therefore, the search for bio fillers for the fabrication of bio‐based composite materials is gaining more and more attention in both academic and industry circles because it promotes sustainability. The present study represents the utilization of biomass solid waste in the hybrid form of Tamarind Seed and Date Seed Filler (TSF/DSF) into polymer reinforced composite which has been explored for the first time by a compression molding technique. These fillers are bio‐waste that can be obtained at a minimal cost from renewable sources. An attempt has been made to use these hybrid fillers to reinforce the matrix ranging from 0 to 50 wt%, and their physical, mechanical, and thermal properties were investigated. In general, the inclusion of hybrid fillers increases mechanical properties, although the addition of hybrid fillers had only a minor impact on thermal properties. When compared to the pure vinyl ester resin, the hybrid fillers reinforced composites revealed a significant enhancement in tensile, flexural, impact, and hardness properties, with improvements of 1.51 times, 1.44 times, 1.87 times, and 1.46 times respectively, at 10 wt% filler loading. Filler matrix interaction of fractured mechanical testing samples was evaluated by scanning electron microscope. Based on the findings, hybrid filler reinforced composites may be suitable for applications where cost is a consideration and where minor compromises in thermal qualities are acceptable. [ABSTRACT FROM AUTHOR]

The present work aims to demonstrate the effect of multiwalled carbon nanotube (MWCNT) on mechanical behavior and damage of woven carbon fiber/epoxy composites through experimental characterizations and multi‐scale modeling. Tensile tests were conducted for MWCNT/epoxy nanocomposites, and carbon nanotube (CNT) reinforced laminated open hole composites with different MWCNT weight ratios. The tensile modulus in CNT/epoxy nanocomposite was enhanced by 15.0%, 37.86%, and 22.86% for MWCNT reinforcement of 0.5%, 1.0%, and 1.5% wt, respectively. The corresponding improvement of tensile modulus for woven composites was 3.45%, 10.25%, and 1.53%; whereas tensile strength was increased by 19.76%, 25.78%, and 6.70%. The enhancement of tensile modulus and strength was less for 1.5% wt MWCNT laminates due to the formation of MWCNT agglomeration. The effective elastic isotropic/orthotropic properties for nanocomposite/woven composite were estimated through Mori‐Tanaka approach and numerical homogenization. The finite element simulations were performed with Hashin's damage model and extended finite element method‐based crack growth study. The delaminations between layers have been demonstrated through cohesive zone modeling. Damage propagation, interface delamination, and fiber/matrix failure were demonstrated by numerical simulations in line with scanning electron microscope observations. [ABSTRACT FROM AUTHOR]

The mechanical and thermal characterization of Moringa oleifera fiber and red mud (RM) reinforced chitosan (CS) based hybrid composite is the subject of this research. By varying the percentages of M. oleifera fiber and RM in the hand lay‐up process, seven types of composite samples were developed. Tensile, flexural, compression, and impact testing were performed in accordance with ASTM standards. A scanning electron microscope was used to examine the cracked surfaces of the tested specimens. Hybridization with M. oleifera fiber and RM increased the characteristics of CS composites, according to the findings. Increase in the percentage composition of RM resulted in better mechanical characteristics of fiber‐reinforced composites. C6 type composite revealed maximum tensile strength of 65.59 MPa and impact strength of 24.86 kJ/m2. It also had better dynamic mechanical qualities, while C6 composite had the best static and dynamic mechanical properties. Overall it may be concluded that composites can be utilized in light weight structural applications. [ABSTRACT FROM AUTHOR]

Herein, the effect of tempering temperature on the microstructure evolution and mechanical properties of a new nitrogen‐containing hot‐work die steel 3Cr7Mo2NiSiVN is investigated. The new type of hot‐work die steel is quenched at 1080 °C and then conducts a double tempering from 200 to 700 °C. The quenching microstructure contains martensite, film‐retained austenite, and undissolved precipitates, and these precipitates play a Zener pinning effect role in prior austenite grains growing. Based on the Thermo‐Calc thermodynamic calculation and experimental results, the die steel contains V‐rich M2N nitride, Cr‐rich M23C6 carbide, Mo‐rich M6C carbide, and (Nb,V)‐rich M(C,N) precipitates. A secondary hardening phenomenon occurs and the brittle fracture turns to ductile fracture under the scanning electron microscope (SEM) field when the tempering temperature is 500 °C. Room strength decreases and the plasticity improves with the continual increase of tempering temperature. Many nano‐size spherical M2N nitride and strip‐like M(C,N) carbonitride precipitate when the tempered temperature exceeds 550 °C with transmission electron microscope (TEM) observation. Finely dispersed M2N nitride and M(C,N) carbonitride are beneficial for stabilizing microstructure at high temperatures and improving high‐temperature strength. Therefore, the high‐temperature strength of the new type of hot‐work die steel is much higher than that of the traditional hot‐work die steel. [ABSTRACT FROM AUTHOR]

Cyanate ester (CE) was employed to modify epoxy resin (EP) by chemical reaction, and the thermal, mechanical, and corrosion properties were systematically studied. Differential scanning calorimetry and Fourier transform infrared spectra were carried out to determine the curing kinetic parameters, suitable curing procedure, and reaction mechanism. The glass transition temperature and thermal stability were investigated employing dynamic mechanical thermal analysis and thermogravimetry measurement. Furthermore, the mechanical and corrosive properties were evaluated, using test techniques such as mechanical testing machine, abrasion tester, axle rod flexibility tester, scanning electron microscope, and electrochemical impedance spectroscopy. Results verified that an appropriate amount of CE could significantly improve the comprehensive performance of EP. However, a satisfactory effect would not be achieved when the modifier is inadequate or excessive. [ABSTRACT FROM AUTHOR]

In the present work, we studied the formation of sunflower oil nanoemulsion using ultrasound techniques. Later, we investigated the development of active films based on a mixture of whey protein containing sunflower oil base nanoemulsion with different concentrations (10, 25, and 50% of total whey protein). The prepared film was by analyzing using the Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and field‐emission scanning electron microscope (FE‐SEM). The film shows no changes in its integrity and crystallinity compared to the virgin film. The presence of nanoemulsion improves the mechanical properties from 2.75 MPa to 3.52 MPa while it decreases the water vapor permeability from 3.4 × 10–10 to 1.3 × 10−10g/m.s.Pa for concentrations NE (50% of Whey protein). The antioxidant activity for Tween 20 nanoemulsion is 38.7% compared to 36.1% for Tween 80 nanoemulsion. The antimicrobial activity of the film contains sunflower nanoemulsion higher than virgin films. The results showed the potential of blend film of whey protein with nanoemulsion for active films for novel food protection. [ABSTRACT FROM AUTHOR]

Additive manufacturing is one of the key technologies for the future production of complex and individualised components. One of the most challenging questions to minimize the production cost is the reuse of the powder leftover after the building process. This study investigates the influence on the mechanical properties when reusing the leftover powder out of the process chamber up to four times. Tensile test specimens are produced and investigated. The results show a decreasing in the ultimate tensile strength with repeated reuse of the leftover powder. After four times of reuse the strength increases again. This cannot be explained by the literature and has to be verified in further investigations. The investigations reveal a high mechanical anisotropy as the strength highly depends on the component orientation in the process chamber. The particle shape does not show any differences between virgin and aged powder under the scanning electron microscope. [ABSTRACT FROM AUTHOR]

This paper reports an experimental study of the influence of elevated temperature on alkali activated slag (AAS) and slag‐metakaolin (MK) systems. The residual compressive and flexural tensile strengths, ultrasonic pulse velocity (UPV) and porosity and water absorption ratios of AAS and AAS‐MK composites after subjected to elevated temperatures of 200, 400, 600, 800, and 1000°C were investigated. Two different procedures were applied for cooling the specimens. The changes in the microstructure of the composites after subjected to high temperature were examined with scanning electron microscope and X‐ray diffraction. Test results reveal that depending on the increasing temperature, the residual compressive strength, flexural tensile strength, and UPV values of the specimens decreased, and porosity and water absorption ratios increased. The minimum strength results of AAS and AAS‐MK specimens were observed at 800 and 600°C, respectively. In particular, there have been significant changes in the internal structure of AAS and AAS‐MK specimens exposed to 1000°C and new reaction products were observed. Test results have shown that AAS specimens are a new alternative that can be developed for use in environments exposed to high temperatures. Since this new composite contains only slag binder and slag aggregate, it can be an economical product that use fully recycled material and these properties can increase the application areas of environmentally friendly material. [ABSTRACT FROM AUTHOR]

Kota stone dust (KSD) and fly ash (FA) are the wastes generated from the construction industry and thermal power plant, respectively. In the present work, a novel hybrid composite is developed to utilize KSD and FA as reinforcing phases in the epoxy matrix. The hand lay‐up method is adopted for the fabrication of 12 sets of samples. Four sets are prepared with single filler KSD and eight samples are prepared with a hybrid combination of KSD and FA. The prepared samples are undergone physical and mechanical tests. To understand the compatibility between filler‐matrix and visualize the dispersion of fillers in epoxy, micrographs are taken using the scanning electron microscope. The density and void contents of the material increases with an increase in filler content. The maximum water absorption measured is 0.96% for the combination of epoxy with 40 wt% KSD and 10 wt% FA. From mechanical testing, maximum tensile strength and flexural strength obtained is 34.4 MPa and 65.4 MPa, respectively, for a combination of epoxy with 20 wt% KSD and 5 wt% FA. Compressive strength and hardness increase with either of the content of the filler and reaches 116.28 MPa and 104 Shore D number, respectively, with 40 wt% KSD and 10 wt% FA. From experimentation, it was found that mechanical properties of the hybrid composites are better as compared to that of single filler composites though physical properties are slightly compromised by hybridization of fillers. [ABSTRACT FROM AUTHOR]

This article investigates the effect of fabrication techniques on the physical, mechanical, and erosion wear properties of glass fiber reinforced dolomite dust‐filled epoxy composites. The composites were fabricated by hand layup and vacuum‐assisted resin transfer molding (VRTM) techniques with fixed glass fiber (20 wt%) and varying dolomite dust (0 to 15 wt%) with epoxy resin. In physical properties, the experimental density consistently increased with the increase in the dolomite hand layup and the VRTM process; in opposite the voids content increased in the hand layup process and decreased in the VRTM process. In mechanical properties, the hardness, impact energy, and interlaminar shear strength increases while tensile and flexural strength consistently decreases with dolomite dust content. Using Taguchi's optimization technique, the erosion wear of the fabricated composites was also evaluated at different impingement angles, impact velocities, and erodent sizes. Erosion test results indicate that the VRTM process fabricated composite has minimum erosion wear compared to the hand layup process. The eroded surfaces were studied using a scanning electron microscope to understand the erosion behavior of particulate‐filled fiber reinforced polymer composites. [ABSTRACT FROM AUTHOR]

This paper emphasis the improvement of mechanical properties of AA7075‐T651 using friction stir processing through localized surface modification by adding nano boron carbide particles. The reinforcement techniques such as the groove and blind hole methods were used by changing reinforcements of nano boron carbide and a matrix of AA7075‐T651 surface composites volume percentages (2 %, 4 %, and 6 %) along with tool rotational speed and processing speeds. Optical microscopy, scanning electron microscope and x‐ray diffraction analysis were used to examine the particle dispersion for the surface composites and to correlate with the enhanced mechanical properties. Results revealed that high input parameters have given grain coarsening and precipitate agglomeration and low input parameters provide poor nugget metal consolidation and no vertical material flow. The L9 orthogonal Array designed and optimized the process parameters for enhancing the surface properties of processed samples. Mechanical properties like ultimate tensile strength, yield strength, hardness, percentage of elongation and impact strength were evaluated for the groove friction stir processing method and blind‐hole friction stir processing methods. From the results, it has been observed that the blind‐hole technique resulted in higher hardness and the homogenous dispersion of nano boron carbide particles in the stir zone than the groove method. Consequently, for blind‐hole friction stir processing, grey relational analysis (GRA) and particle swarm optimization (PSO) approaches were proposed to optimise process parameters. From the compared optimization results between grey relational analysis and particle swarm optimization, particle swarm optimization approach was shown the best optimization results. Successively, the optimum condition in the respective experimentation is accomplished. Based on these observation and results, final validation tests were carried by changing the volume percentages of reinforcement keeping tool rotation speed and tool processing speed as constant. It is apparent that dynamic recrystallization in aluminium alloy at the processed zone due to presence of heterogeneous nucleation sites with nano boron carbide particles. [ABSTRACT FROM AUTHOR]

The present research focuses on studying the physical, mechanical, and abrasive wear behavior of the hemp/nettle natural fiber woven mat reinforced with the polyester matrix. The hemp and nettle fibers woven mats were reinforced into the polyester matrix by simple hand‐layup, and after that compression molding process was used to fabricate the composites. The water absorption, tensile, flexural, and impact properties were studied using a hemp/nettle hybrid composite. This study found that increasing the amount of hemp and nettle fiber in polyester from 3 to 9 wt% increased the mechanical properties of hybrid composites. The higher weight percentage (9 wt%) of hemp/nettle fiber in polyester hybrid composites exhibited the highest tensile (42.41 MPa), flexural (78.52 MPa), impact (22.72 kJ/m2) strength, and a higher hardness value of 46.7 HV. Finite element analysis simulation is conducted on mechanical properties (tensile, flexural, and impact strength). The minimum abrasive specific wear rate of hybrid composites is 0.00827 mm3/Nm found in the 9 wt% of hemp/nettle fiber composite at 10 N of normal load and 200 RPM, through Taguchi's approach (L9 orthogonal array). The contribution of control factors in a hybrid composite is studied by analysis of variance. The surface morphological studies were performed to examine the abraded worn surface by abrasive wear to study the behavior of the wear mechanism using the scanning electron microscope. [ABSTRACT FROM AUTHOR]

Additive manufacturing technology can help us to produce complex components/parts easily. It can be used to develop the parts with multi‐material structures consisting of thermoplastic, thermosetting plastic, and ceramic fibers. This multi‐material structure enhances the performance of lightweight polymer‐based components. In this research work, poly‐lactic acid (PLA) lattice (mono‐material structure), PLA lattice filled with epoxy (bi‐material structure), and PLA lattice incorporated with embedded milled glass fibers (MGFs) in an epoxy matrix (tri‐material structure, TMS) were designed and developed by fused filament fabrication and solution casting methods. PLA lattice of 50% volume was fixed in all structures and 50% volume was filled with epoxy and MGFs. The dispersed MGFs in epoxy matrix were varied from 0, 2.5, 5, and 7.5 vol%. The mechanical properties were carried out by compression test, three‐point bending test, and tensile test. The results revealed that 5 vol% of MGFs in the epoxy sample (TMS) exhibited improved mechanical performances compared to other samples. The cone‐beam CT scan results confirmed the voids/porous free surfaces in the developed materials. The high‐resolution scanning electron microscope microstructural evolutions in‐terms of topography and fractured regions were also examined and reported. [ABSTRACT FROM AUTHOR]

Zirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2/(Ar+N2)] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X‐ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal α‐Zr phase to cubic c‐Zr and then to mixed α‐Zr and face centered cubic c‐ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank's solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples. [ABSTRACT FROM AUTHOR]

This research work investigates the influence of hybrid particulate fillers, Mg–Al layered double hydroxide (LDH), and nanoclay (NC), on the mechanical properties and formability of glass laminate AA5052 epoxy composites (GLARE). The composite laminates were prepared by varying the weight percentage (i.e., 3, 4, and 5 wt%) of the hybrid fillers in the epoxy resin. The conventional hand layup technique was utilized for the fabrication of the laminates. The tensile test samples were prepared in different orientations with respect to the rolling direction (i.e., 0°, 45°, and 90°) to address their anisotropic nature. The flexural, impact, lap shear, and formability tests were conducted as per ASTM and IS standards. The Erichsen cupping test was performed to study the formability of the composite laminates. For each test, the results were compared with that of the laminates containing individual LDH filler, NC filler, and no filler material. The results showed that the composite laminate with 5 wt% of LDH + NC hybrid filler exhibited enhanced tensile properties, impact energy, and lap shear strength while the laminate of 4 wt% LDH + NC filler possessed better flexural properties. The formability of the composite laminates with hybrid LDH + NC fillers was observed to be lower than that of the laminates with individual filler materials and laminate without any filler. The variation observed in the test results was justified by investigating the failure mechanism of the composite laminates using a scanning electron microscope. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the thickness influence on the efficiency of multiwalled carbon nanotubes (MWCNTs) in glass/epoxy composite laminates under the high‐velocity impact. Combining 0.25 wt% of MWCNTs in the 4‐layer and 8‐layer specimens and 0.1 wt% of MWCNTs in the 16‐layer specimen led to the maximum rise in the energy absorption and specific perforation energy compared with the unreinforced laminates. The significant growth in energy absorption in the 4‐layer, 8‐layer, and 16‐layer specimens was 5.8, 8.3, and 14.4 J, respectively. The number of agglomerations (dislocations) in the matrix was consequently increased as a function of thickness, which led to the better performance of MWCNTs with lower weight percentages in the composite laminates containing more layers. The scanning electron microscope was used to observe the dispersion and agglomeration of MWCNTs in the resin epoxy, and there was also an improvement in the fiber–resin bonding. [ABSTRACT FROM AUTHOR]

In this paper, SiC coating was prepared using the polymer‐derived ceramic method; then the effect of nano‐alumina as a filler material was studied. First of all, polycarbosilane(PCS) was dissolved in xylene; after that, different amounts of nano‐alumina particles were added to the solution. The coating was deposited on the alumina substrate using the dip‐coating method; this was followed by sintering at 1200℃. The phase content and microstructure of the samples were studied by X‐ray diffraction and scanning electron microscope methods, respectively. Nanohardness, Young's modulus, and coating adhesion were investigated by a nanoindentation method. The sheet resistance was evaluated using the four‐point probe technique; also, the wear resistance of the coating was studied by applying the pin‐on‐disk method. It was found that the addition of the nano‐alumina filler up to 20 wt% drastically improved the adhesion and wear resistance of the SiC coating. [ABSTRACT FROM AUTHOR]

This work investigates the effect of different loading of copper alumina nanoparticles (Cu‐Al2O3) on the processing characteristics, crystalline, morphological, mechanical, and thermal properties of natural rubber (NR). The effective reinforcement of Cu‐Al2O3 nanoparticles into NR was carried out using a simple and efficient two roll mill mixing technique and the structural changes were systematically analyzed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscope (SEM), high‐resolution transmission electron microscope (HR‐TEM), differential scanning calorimetry, and thermogravimetric analysis. The FTIR and XRD of NR/Cu‐Al2O3 showed the characteristic absorption bands and the crystalline peaks of Cu‐Al2O3 in the prepared composites. SEM and HR‐TEM showed the uniform distribution of nano Cu‐Al2O3 in the NR matrix. The processing time of the nanocomposites was significantly decreased with the addition of metal oxide nanoparticles, which indicated the reduction in the cost of the fabrication of elastomer product using Cu‐Al2O3 nanoparticles. Mechanical properties such as modulus, tensile strength, hardness, heat build‐up, glass transition temperature, tear properties, abrasion, and thermal stability were greatly enhanced by the reinforcement of Cu‐Al2O3 into the NR matrix. The swelling behavior of composite with respect to different loading of nano‐filler was also investigated in various aromatic solvents. The addition of nanoparticles reduces the solvent uptake of the composite and the maximum solvent resistance was noted for the composite with 5 phr loading. [ABSTRACT FROM AUTHOR]

Lattice structures are characterized by good mechanical efficiency because their particular geometry confers high strength and stiffness coupled to lightweight. These structures can be produced using a wide range of technologies, but the additive manufacturing ones are the most promising. In this work, the flexural properties of titanium alloy lattice structure made by means of electron beam melting process were investigated through the three‐point bending test, carried out with three different span lengths. It was found that the span length influenced the load–displacement trend; moreover, the lower skin failure was observed in all the test conditions considered, but for the shortest span, the indentation of upper skin was found, too. The scanning electron microscope analysis showed the presence of dimples on the fracture surface, denoting a ductile fracture behavior. [ABSTRACT FROM AUTHOR]

Dental fractures of the anterior teeth are a common form of dental trauma. Reattachment of fractured tooth fragment by means of self‐adhesive resin cement is currently compromised by the poor mechanical properties of these ceramics. Herein, we synthesized zirconium dioxide nanoparticles (nano‐ZrO2) using the Co‐precipitation approach and then mixing it in different concentrations (1.0, 2.0, 3.0, and 5.0 wt%) with the commercially available RelyX™ Unicem self‐adhesive universal resin cement (ARC) forming, nano‐ZrO2/ARC. Both the synthesized nano‐ZrO2 and nano‐ZrO2/ARC were characterized using a high‐resolution transmission electron microscope (HR‐TEM), field‐emission scanning electron microscope, X‐ray diffraction, and Fourier transform infrared technique. The HR‐TEM images revealed that the synthesized nano‐ZrO2 was spherical with a size of ~ 12 nm. The results showed that the addition of nano‐ZrO2 significantly enhanced the mechanical properties as fracture resistance, compressive strength, diametral tensile, and micro‐hardness values of the resin cement. The mixing 3.0 wt% of nano‐ZrO2 with ARC revealed the maximum improvement in the mechanical properties and, consequently, the resin's repair strength. Their incorporation with ARC up to 3.0% wt did not cause significant cell death than ARC alone. We believe that the information discussed here might be relevant to the stability of nano‐ZrO2‐modified resin cement and, therefore, to its clinical usage for fragment tooth reattachment, cementation of dental crowns, bridges, and bands. [ABSTRACT FROM AUTHOR]

A 3D architecture carbon fiber preform, specifically fine‐woven cloth and punctured felt preform, is used to manufacture a novel advanced Cf/C‐SiC‐ZrC composite. The composite matrix is produced by chemical vapor infiltration (CVI) plus precursor infiltration and pyrolysis (PIP) process and finalized by using a chemical vapor deposition (CVD) of SiC coating to make the final density of the material reach 1.95 g/cm3. The organic precursors of SiC and ZrC have a weight ratio of 4:1 in a xylene solute. The composite mechanical properties, such as tensile, compression, bending, shear, and Z‐direction load bearing, are introduced under analysis to find possible applications for the composite. What is more, scanning electron microscope (SEM) images are employed to illustrate the failure behavior of the ceramic composite. The results showed that the punctured filament tows will be beneficial, not only for the composite to withstand compression force up to 308.6 MPa and shear strength to 18.14 MPa but also for the alternatively stacked weave piles and short fiber layers to support the punctured bundles, as well as to hold the composite structure under mechanical forces from different orientations, which is believed to reinforce the ceramic matrix for some high pressure and severe ablation applications. [ABSTRACT FROM AUTHOR]

The hardness and toughness of regenerated cemented carbides, in general, are contradictory. Therefore, it is critical to explore regenerated cemented carbides with both high hardness and high toughness. In this study, regenerated WC‐8‐wt% Co cemented carbide with SiC nanowhisker were prepared by low‐pressure sintering. The influence of SiCw contents on the microstructure and mechanical properties of regenerated WC‐8‐wt% Co cemented carbide was investigated. The results indicated that the hardness, density, flexural strength, and fracture toughness of regenerated cemented carbide first increased and then decreased with the addition of SiCw. The Vickers hardness, density, flexural strength, and fracture toughness could reach 1575 HV, 14.6 g/cm3, 2204 MPa, 16.85 MPa·m1/2, respectively, with SiCw content 0.5 wt%, which were increased by 14.4%, 0.7%, 12.2%, and 17.3%, respectively, when compared with the regenerated cemented carbide without SiCw. The lowest friction coefficient and the best wear resistance could be also reached when 0.5‐wt% SiCw was added. The fracture mechanism of the regenerated cemented carbide contained both transgranular and intergranular fracture through the microscopic observation of fracture surface via scanning electron microscope. [ABSTRACT FROM AUTHOR]

Polyurethane/Graphite composite foam samples with different filler loadings were synthesized for application in electromagnetic shielding. The samples were characterized using Fourier transform infra‐red, thermal gravimetric analysis, scanning electron microscope, universal testing machine, and rheometer. Moreover, to adapt and customize this work in the field of aerospace, the measurements were performed in the X‐band at the range of (8–12) GHz. The results showed that the increase in filler content improves the mechanical properties and thermal stability of the composite materials. The electromagnetic interference shielding effectiveness reached (− 45) dB with 30 wt% filler content. It is expected that the polyurethane/graphite composite foamy materials may be considered a promising material to be used in electromagnetic shielding applications. [ABSTRACT FROM AUTHOR]

High‐performance composites reinforced with natural fibers are next‐generation structural materials due to their recyclability and light weight. Manufacturing composites with high strength has been a challenge. Here, we describe the manufacture of novel composites reinforced with wood fibers using densification by hot‐pressing and fixing by curing reaction with phenolic resin. This composite with 1.4 g/cm3 had high mechanical properties, high water stability, and aging‐resistance, and exhibited a flexural strength and internal bonding strength of 102.4 and 7.5 MPa, respectively. The strength and modulus are 1.5–6.0 and 1.3–28.1 times higher than those of most of the wood fibers reinforced composites. After immersing in water for 24 h, the water absorption and thickness swelling are only 1.3% and 0.8%, respectively. Scanning electron microscope characterization indicates that the cell wall is totally collapsed and became complete densification. And the collapsed cells are fixed by phenolic resin. This production strategy for the composites was shown to be universally effective for various species of natural fibers. These novel wood fiber‐reinforced composites were suitable for commercial manufacture in the current production line, making them a low cost and high‐performance alternative to automotive and aerospace industries. [ABSTRACT FROM AUTHOR]